Process of softening water.



UNITED STATES PATENT OFFICE.

HUGO HELLER, OF COLOGNE, GERMANY, ASSIGNOR TO OELWERKE STERN SONNEIBORN AKT. GES., OF COLOGNE, GERMANY.

PROCESS OF SOFTENING WATER.

No Drawing.

Toall whom it may concern:

Be it known that I, Huoo HELLER, a subject of the Emperor of Austria, residing at Cologne, Germany, Luxemburgerstrasse 150, have invented certain new and useful Improvements in Processes of Softening Wa 1 tubes of a boiler and cannot therefore be used.

According to the present invention the substance commonly or commercially known as phosphate of sodium (namely the sec-- ondary salt HNa PO is employed and the improved process comprises the addition of a suitable amount thereof to the water to be treated and raising'the temperature of the water to the boiling point, the boiling being preferably continued for a few minutes.

.The principal reactions may be illustrated by the following equations:

By such method or process it is possible to soften water to a degree unobtainable by the process heretofore employed and in a considerably shorter period of time than has been previously required.

Asa specific example of how the process may be carried out and the results obtained thereby it is to be noted that when approximately 4 com. of a ten per cent. solution of di-sodium phosphate (HNa,PO was added to 100 com. of water without heating the water the degree of hardness thereof, which was originally about 7.0", was reduced to approximately 426. By keeping the water at a temperature of 70 C. for half an hour the hardness was reduced to 1.7 5. After being maintained at a boiling temperature- Specifieation of Letters Patent.

Patented July 30, 1918.

Application filed November 13, 1914. Serial No. 872,031.

for five minutes the hardness of the Water was -1.65 and at the expiration of ten min-.

utes only 1. The removal of the resulting precipitate is eflected before the water enters the boiler.

The boiling of the watercontaining disodium phosphate for from five to ten minutes presents advantages of considerable importance. The principal advant e is that the sodium bi-carbonate which is ormed as a result of the initial reaction of the di-sodium phosphate is only partly decomposed by bringing the Water up to a boiling temperature whereas the decomposition into thenormal sodium carbonate and free carbon dioxid is almost complete by continuing the boiling for about ten minutes. If the bicarbonate had not been thus broken up before the water entered the boiler, the liberation of carbon dioxid would occur in the boiler and would have an injurious action on the boiler. The boiling also offers a more economical use of the softening reagent since the normal sodium carbonate which is formed by the boiling itself acts as a softening agent by reacting with the calcium or magnesium sulfates that may be present. It will thus be seen that all of the sodium is thus made effective as a softening agent by boiling, instead of part of it beinglost as sodium bicarbonate. Among other advantages of boiling there may be mentioned the more efficient driving off of air that is normally contained in water.

The advantages of the improved process in comparison with those heretofore proposed'for the same purpose will be readily appreciated. It will be seen that the process makes it possible to soften water to such a degree that it can be freely'used in steam boilers without danger of damage to the Walls or tubes and from which the danger of formation of scale is reduced to a minimum. v

Having thus described the invention what is claimed is 1. The herein described process of softening water for use in steam boilers comprising treating the water with di-sodium phosphate and heating it. i

2. The herein described process of softenthe water and then boiling it for from five ing Water for use in steam boilers Which to ten minutes. u 10 comprises adding di-sodium phosphate to In testimony whereof I afiix my signature the Water and thereafter boiling it for a few in presence of two witnesses.

5 minutes. HUGO HELLER.

3. The herein described process of soften- Witnesses: ing Water for use in steam boilers which J. WYNEN,

comprises adding di-sodium phosphate to J. D. ZIESECKY. 

